Question

Q1. When baking soda is mixed with lemon juice, bubbles are formed with the evolution
of a gas. What type of change is it? Explain.
Q2. Give four properties of physical and chemical changes.
Q3) If you leave a piece of iron in the open for a few days, it acquires a film of
brownish substance, called rust.
(a) Do you think rust is different from iron?
(b) Can you change rust back into iron by some simple method?
(C) Do you think formation of rust from iron is a chemical change?
(d) Give two other examples of a similar type of change.​

Answer 1

Answer:

1. When baking soda mixed with lemon acid base CO2 is evolved. it is a chemical change.

Explanation:

2.

3. Rust is different from iron.

Rusting is irreversible process.

Ya it's it's chemical change.

Similar changes r curdling of milk.

Buring of paper.